Sound reproducing system and method for portable terminal device

ABSTRACT

A portable information terminal having high adaptability and high convenience with respect to operating environment, and by which comfortable and high-quality sounds can be reproduced is provided.  
     A sound reproducing system in a portable information terminal  1,  wherein the portable information terminal is provided with at least two acoustic loudspeakers  2   a  and  2   b ; and the at least two acoustic loudspeakers are driven simultaneously to compensate their reproduced sounds with each other.

TECHNICAL FIELD

[0001] The present invention relates to portable information terminals,including radio telephone, such as cellular phone, PHS (Personal HandyPhone System), cordless phone, cordless handset of extension phone, andPDA (Personal Digital Assistants), and particularly to a soundreproducing system in portable information terminals for realizing soundreproduction of high acousticity and a method therefor.

BACKGROUND ART

[0002] With respect to installation of speakers and the like in portableinformation terminals such as conventional cellular phone, ringer forsounding bell sounds, micro motor for producing vibrations or the likehas been attached to a cabinet for portable information terminals as ameans for receiving call incoming.

[0003] Furthermore, it is usual to attach a micro speaker forreproducing received sounds or amplifying recorded messages, and amicrophone for collecting voice being fundamental functions in portableinformation terminal, respectively.

[0004] Japanese Patent Laid-Open No. H10-276250 discloses that stereosounds are listened by users with the use of earphones or headphones inportable information terminals.

[0005] In this case, however, there are such disadvantages thatunpleasant ache appears at a position where user's ears are in contactwith a earphone or a headphone for a long period of time, and that theearphone or headphone must be carried together with the portableinformation terminal in case of user's movement. Besides, plural personscannot listen stereo sounds at the same time, so that there has beensuch a problem that it is insufficient in view of comfortableness andconvenience.

[0006] Moreover, Japanese Patent Laid-Open No. H8-171477 discloses aworkstation and the like for personal computer (PC), and Japanese PatentLaid-open No. H9-120354 discloses reproduction of stereo sounds by meansof a loudspeaker without accompanying an earphone and a headphone withrespect to notebook-size personal computer.

[0007] In reproduction of stereo sounds through loudspeakers, spatialextensity is required for a sound source, while there is a possibilityof appearing cross talk as mentioned hereunder, which is not experiencedby the use of earphones or headphones. For this reason, a distancedefined between right and left loudspeakers must be maintained at agiven distance or more, and an acoustic pressure difference and a phasedifference between both ears of an audience must be maintained at agiven value or more, respectively, with respect to the right and leftloudspeakers.

[0008] In this connection, when a distance defined between the right andleft loudspeakers is made to be small so that an acoustic pressuredifference and a phase difference between ears of the audience decreaserespectively, with respect to the right and left loudspeakers, stereosound effects decrease due to cross talk, resulting in substantiallymonaural sounds.

[0009] In this respect, since a portable information terminal is morecompact than the above-described personal computer and the like, adistance between right and left loudspeakers becomes narrower, so thatit is difficult to maintain stereo sound effects, whereby there is sucha problem that it is difficult to reproduce stereo sounds with highacousticity.

[0010] Incidentally, a tendency of multimedia portable informationterminal becomes remarkable in recent years, so that mass storage datasuch as picture image and music must be handled because of increase in acapacity of built-in memory, introduction of a storage medium, andhigh-speed of communication in portable information terminals.

[0011] Moreover, an ownership ratio of portable information terminalsincluding cellular phone is remarkable, and in addition, many personstake along such portable information terminal in case of outing, so thatthere is a task for elevating convenience to add other extra functionsto portable information terminals.

[0012] In order to listen high-quality and comfortable sounds derivedfrom multimedia data by means of a portable information terminal, thereis such a task that not only stereo sound reproduction of comfortablesounds is required, but also broadband property in frequency of thesounds must be maintained to assure high-quality sounds with respect toportable information terminals.

[0013] Furthermore, there is such a task that maintenance of directivityin sounds is required for portable information terminal to listen thesame by a plurality of persons in a restricted region, to avoidharassment with respect to surrounding people,

to be suitable for operating environment with respect to portableinformation terminals.

[0014] On the contrary to that described above, there is such a taskthat omnidirectional characteristics of sounds are to be maintained forlistening such sounds by much more persons.

[0015] Besides, there is a task of requiring such convenience that twoor more persons can catch individually two or more languages or soundsources.

[0016] Accordingly, the present invention has been made in view of theabove-described problems and tasks. An object of the present inventionis to provide a sound reproducing system in portable informationterminal, which can reproduce comfortable, high-quality sounds and hashigh adaptability to operating environment as well as high convenience,and a method therefor.

DISCLOSURE OF THE INVENTION

[0017] In order to eliminate the above-described problems, the presentinvention provides a reproducing system in a portable informationterminal characterized by that the portable information terminal isprovided with at least two acoustic loudspeakers; and the at least twoacoustic loudspeakers are driven simultaneously to compensate theirreproduced sounds with each other.

[0018] According to this means, the portable information terminal canreproduce comfortable and high-quality sounds, and as a result, theportable information terminal comes to have high adaptability and highconvenience with respect to operating environment.

[0019] Preferably, the above described at least two acousticloudspeakers are either disposed on the portable information terminal ina longitudinal direction thereof, or disposed diagonally at the oppositeends of the portable information terminal.

[0020] According to this means, cross talk between acoustic loudspeakersappeared in case of reproducing stereo sounds can be avoided, so that itbecomes possible to reproduce stereo sounds of high acousticity in theportable information terminal.

[0021] Preferably, one or all the members selected from the abovedescribed at least two acoustic loudspeakers is located at a certainangle with respect to a cabinet wall of the portable informationterminal.

[0022] According to this means, propagating directions of sounds from atleast two acoustic loudspeakers direct to a listener in the case whenthe portable information terminal is placed on a low place such as adesk, and a floor, so that reproduced sounds become easy to listen.Moreover, in case of a compact portable information terminal, at leasttwo acoustic loudspeakers direct outwards to each other, whereby it ispossible to avoid cross talk to be produced between the acousticloudspeakers.

[0023] Preferably, each angle defined between one or all the acousticloudspeakers selected from the above described at least two acousticloudspeakers and the cabinet wall of the portable information terminalcan be freely changed.

[0024] More preferably, each angle of one or all the above described atleast two acoustic loudspeakers may be mutually and freely changed.

[0025] According to these means, an angle or angles of the acousticloudspeaker(s) can be arbitrarily changed dependent upon a position of alistener with respect to the portable information terminal, and asituation of compactness of the portable information terminal.

[0026] Preferably, a cross talk barrier is placed between theabove-described at least two acoustic loudspeakers, so that the crosstalk barrier prevents from generating cross talk from individualacoustic loudspeakers.

[0027] According to this means, cross talk components produced in thecase where the at least two acoustic loudspeakers are very close to eachother are physically eliminated.

[0028] Preferably, the above-described cross talk barrier is collapsibleor detachable.

[0029] According to this means, it is prevented from occurring damage ofthe cross talk barrier due to being hooked by any protruded member inthe case where no acoustic loudspeaker is required, and the portableinformation terminal is carried.

[0030] Preferably, the above-described portable information terminal isprovided with a signal processing circuit for eliminating cross talk; sothat the signal processing circuit for eliminating cross talk processesinput signals of the above-described at least two acoustic loudspeakersto eliminate cross talk.

[0031] According to this means, it becomes possible to eliminate crosstalk produced between the acoustic loudspeakers without accompanying across talk barrier.

[0032] Preferably, at least one member selected from the above describedat least two acoustic loudspeakers is located at a fallen place from aposition of a cabinet wall of the portable information terminal.

[0033] According to this means, a protruded section towards the outsideis reduced to be able to realize a cross talk barrier being lessprotrusive.

[0034] Preferably, either a part or the whole of the above-described atleast one acoustic loudspeaker is covered with a perforated section of acabinet wall of the portable information terminal, or a cabinet wallcovering a vibrating surface of the loudspeaker is removed.

[0035] According to this means, it is possible to elevate a soundpressure of sounds from loudspeakers.

[0036] Preferably, at least one acoustic loudspeaker is protruded from aside of opposite ends of the portable information terminal.

[0037] According to this means, a distance between the acousticloudspeakers is broadened, so that cross talk can be reduced, whereby itbecomes possible to reproduce stereo sounds of high acousticity withoutemploying a cross talk barrier.

[0038] Preferably, the above-described at least one acoustic loudspeakeris located at a deeper position from the front of the portableinformation terminal; and either a part of the above-described at leastone acoustic loudspeaker is covered with a perforated section of acabinet wall of the portable information terminal, or a cabinet wallcovering a vibrating surface of the at least one acoustic loudspeaker isremoved.

[0039] According to this means, a distance between the acousticloudspeakers is broadened, so that cross talk can be reduced, whereby itbecomes possible to reproduce stereo sounds of high acousticity, besidesit is possible to increase a sound pressure of the acoustic loudspeakerswithout employing a cross talk barrier.

[0040] Preferably, the above described at least one protruded acousticloudspeaker is contained inside the portable information terminal.

[0041] According to this means, the protruded acoustic loudspeaker iscontained inside the portable information terminal in case of carryingthe same, so that a trouble of being hooked by anything can be avoidedin case of portage.

[0042] Preferably, the above described at least two acousticloudspeakers are arranged in a row of a speaker array in the portableinformation terminal.

[0043] According to this means, since directivity is improved in adirection of the speaker array, it is possible to arrange in such thatsounds are delivered only to a small number of listeners, but not to thethird party, so that listening of sounds in which harassment withrespect to a surrounding area can be avoided without employing headphoneand the like in the case where sounds are listened by a small number ofthe listeners in a place such as coffee house by means of the presentportable information terminal 1.

[0044] Preferably, the above described at least two acousticloudspeakers are arranged in the portable information terminal so as todirect different directions from one another.

[0045] According to this means, since the acoustic loudspeakers can beset outwards to each other, cross talk in sounds of the acousticloudspeakers decreases, so that reproduction of stereo sounds of highacousticity can be realized. Moreover, when acoustic loudspeakers aredisposed towards every sides of the portable information terminal,higher effect of omnidirection can be achieved, and this is convenientin case of making a number of listeners to listen sounds.

[0046] Preferably, the above described at least two acousticloudspeakers reproduce sounds in such that different sounds are listenedindividually in different directions.

[0047] According to this means, it becomes possible that, for example,voices of two different languages are listened by a plurality ofpersons, and a plurality of languages is listened at the same time asindividually different sounds by the use of a single portableinformation terminal 1.

[0048] Preferably, the above-described portable information terminal isprovided with a signal processing circuit for converging directivity;and the signal processing circuit for converging directivity processesinput signals of the above-described at least two acoustic loudspeakersto converge directions of directivity.

[0049] According to this means, directivity of acoustic soundpropagation is converged in a certain direction as a result of signalprocessing by means of a small number of acoustic loudspeakers.

[0050] Preferably, the portable information terminal is provided with anomnidirectional signal processing circuit; and the omnidirectionalsignal processing circuit processes input signals of the above-describedat least two acoustic loudspeakers to make them omnidirectional.

[0051] According to this means, omnidirection wherein acoustic soundpropagation expands more widely by means of a small number of acousticloudspeakers is realized, whereby it becomes possible to listen soundsby a number of listeners with the use of a single portable informationterminal without increasing acoustic loudspeakers.

[0052] Preferably, the portable information terminal is provided with asignal processing circuit for converging directions of theabove-described at least two acoustic loudspeakers with respect to theirdirectivities and an omnidirectional signal processing circuit formaking the above-described at least two acoustic loudspeakersomnidirectional; and the signal processing circuit for convergingdirectivity and the omnidirectional signal processing circuit areselected alternatively.

[0053] According to this means, since signal processing functions aremade to be selectable, it becomes possible to implement the optimumsignal processing, besides it becomes possible to listen alwayscomfortable sounds.

[0054] Preferably, the above described at least two acousticloudspeakers having high efficiency are used, whereby it becomespossible to drive the above described at least two acoustic loudspeakersin case of reproducing sounds without employing any amplifier.

[0055] According to this means, acoustic loudspeakers having highefficiency are used to operate the same without employing any amplifier.Thus, since no amplifier is required as described above, the number ofparts to be used in a portable information terminal decreases, a compactand light-weight portable information terminal can be realized, and lowpower consumption can be realized, so that an available time by a singlecharge increases in the portable information terminal.

[0056] Preferably, individual sounds are reproduced from the abovedescribed at least two acoustic loudspeakers; and sound volumes of theindividual sounds can be uniquely adjusted.

[0057] According to this means, when a foreign language is learned, forexample, while listening two languages including native language,learning efficiency can be elevated by listening the foreign languagewith a larger sound volume than that of the native language.

[0058] Preferably, the above described at least two acousticloudspeakers have characteristics specialized to middle- to high-pitchedtone ranges, and that specialized to a low-pitched tone range,respectively.

[0059] According to this means, it becomes possible to reproduce soundsof higher acousticity in a high bandwidth.

[0060] Preferably, the above-described at least two acousticloudspeakers are arranged in such that when the portable informationterminal is placed to be in contact with a plane including a desk, afloor, and a wall surface, the above-described at least two acousticloudspeakers can utilize reflection of sounds.

[0061] According to this means, it becomes possible that when theportable information terminal 1 is in contact with a plane of desk orthe like, low note components are reflected by the plane of desk toreverse a phase thereof, so that the low note components come to havethe same phase as that come out from the front of the acousticloudspeakers, whereby the low note components coming out frontward canbe reinforced.

[0062] Preferably, the above described at least two acousticloudspeakers can reproduce sounds simultaneously with a communication bymeans of the portable information terminal. More preferably, acousticsound reproducing signals of the above described at least two acousticloudspeakers are transmitted so as to be able to listen also by theother party for communication.

[0063] According to this means, it becomes possible to realize aconversation accompanied with BGM by the use of the portable informationterminal.

[0064] Preferably, at least one member selected from the above-describedat least two acoustic loudspeakers is the one serving both as a acousticloudspeaker and a device of the portable information terminal includingan acoustic loudspeaker serving also as a speaking microphone, anacoustic loudspeaker serving also as a receiving speaker, an acousticloudspeaker serving also as a ringer, an acoustic loudspeaker servingalso as a vibrator, an acoustic loudspeaker serving also as a screendisplay monitor, and an acoustic loudspeaker serving also as a keypanel.

[0065] According to this means, since an acoustic loudspeaker servesalso as a device, the number of parts to be used in the portableinformation terminal decreases, whereby downsizing and weight reductionof the portable information terminal can be achieved.

[0066] Preferably, an acoustic signal generator is connected to theabove-described portable information terminal; the acoustic signalgenerator stores acoustic sound data; and the above-described at leasttwo acoustic loudspeakers reproduce sounds based on the acoustic sounddata obtained from the acoustic signal generator.

[0067] According to this means, when the portable information terminalis allowed to function as an external acoustic loudspeaker and adding afunction for reproducing sounds from other sound source, the portableinformation terminal becomes possible to respond much more sound data,and in addition, it becomes unnecessary for carrying separately anyacoustic loudspeaker other than the portable information terminal.

[0068] Preferably, a plurality of the above-described acoustic signalgenerators is connected to the portable information terminal; and any ofthe acoustic signal generators from which data is to be acquired ischanged over by a switch.

[0069] According to this means, for example, sounds derived from aplurality of sound sources can be easily compared with each other,whereby convenience can be elevated.

[0070] Preferably, the above-described at least two acousticloudspeakers are allowed to be able to reproduce sounds withoutemploying any amplifier; and they are made to be able to reproducesounds of the acoustic sound data obtained from the above-describedacoustic signal generator in a condition where a power supply in theportable information terminal itself has been shut off.

[0071] According to this means, it becomes possible to reproduce soundsunder a condition where a power supply is shut off in a portableinformation terminal itself in case of reproducing input signals fromthe outside. As a result, electricity for the portable informationterminal is saved to increase a serviceable time for a single charge,whereby it becomes possible to reproduce sounds of high acousticityirrespective of a remaining amount of battery.

[0072] Preferably, the above-described portable information terminalacquires data from the above-described acoustic signal generator throughradio wave.

[0073] For this means, a means such as Bluetooth is applicable, so thatno cable is required, whereby a constitution of system can besimplified.

[0074] Preferably, a headphone or an earphone is connected to theportable information terminal; and reproduced sounds are listened bymeans of the headphone or earphone in place of the above described atleast two acoustic loudspeakers.

[0075] More preferably, reproduced sounds from the above described atleast two acoustic loudspeakers are listened simultaneously with acommunication message in the portable information terminal by means ofthe above-described headphone or earphone.

[0076] According to these means, no remarkable harassment arises withrespect to a surrounding area, and communication accompanied withcomfortable BGM can be realized through telephone conversation.Furthermore, when any of sounds of noise in station, hustle and bustle,pink gin in department store, lush house and the like is selected as abackground effect, more pleasant communication can be promoted.

[0077] Preferably, the above-described portable information terminal isextensible, and more preferably, the above-described portableinformation terminal is collapsible.

[0078] According to these means, the present invention is alsoapplicable for an extensible or collapsible type portable informationterminal, besides reproduction of stereo sounds of high acousticity ispossible.

[0079] Furthermore, a method for reproducing sounds in a portableinformation terminal according to the present invention is characterizedby that at least two acoustic loudspeakers disposed in the portableinformation terminal are driven at the same time to compensatereproduced sounds with each other.

[0080] According to this means, a portable information terminal canreproduce comfortable and high-quality sounds as in the above-mentionedinvention, whereby the portable information terminal became to have highadaptability and high convenience with respect to operating environment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0081]FIG. 1 is a view showing a schematic structure of a firstembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0082]FIG. 2 is a view for explaining stereo sound reproduction by meansof acoustic loudspeakers 2 a and 2 b of FIG. 1;

[0083] FIGS. 3(a) and 3(b) are views each showing a schematic structureof a second embodiment of a sound reproducing system in a portableinformation terminal according to the present invention;

[0084]FIG. 4 is a view showing a schematic structure of a thirdembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0085]FIG. 5 is a sectional view taken along the line either Ba-Ba′ orBb-Bb′ of FIG. 4;

[0086]FIG. 6 is a view showing a schematic structure of a fourthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0087]FIG. 7 is a sectional view taken along the line B-B′ of FIG. 6;

[0088] FIGS. 8(a) and 8(b) are diagrams each explaining for decrease incross talk of acoustic loudspeakers 2 a and 2 b shown in FIGS. 6 and 7;

[0089]FIG. 9 is a view showing a schematic structure of a fifthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0090]FIG. 10 is a view showing a schematic structure of a sixthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0091]FIG. 11 is a view showing a schematic structure of a seventhembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0092]FIG. 12 is a schematic constitutional view of A-A′ sectioninvolving acoustic loudspeakers 2 a and 2 b in FIG. 11 viewed from adirection of the arrow;

[0093] FIGS. 13(a) and 13(b) are diagrams each explaining for decreasein cross talk of acoustic loudspeakers 2 a and 2 b shown in FIGS. 11 and12;

[0094]FIG. 14 is a diagram showing a second modified example of aschematic structure of the seventh embodiment in FIG. 11;

[0095]FIG. 15 is a diagram showing a third modified example of aschematic structure of the seventh embodiment in FIG. 11;

[0096]FIG. 16 is a view showing a schematic structure of a eighthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0097]FIG. 17 is a view showing a schematic structure of a ninthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0098]FIG. 18 is a view showing a schematic structure of a tenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0099]FIG. 19 is a view showing a schematic structure of a eleventhembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0100]FIG. 20 is a schematic constitutional view of A-A′ sectioninvolving acoustic loudspeakers 2 a and 2 b in FIG. 19 viewed from adirection of the arrow;

[0101]FIG. 21 is a schematic diagram showing a circuit for executingsignal processing of cross talk elimination;

[0102] FIGS. 22(a) and 22(b) are schematic diagrams each explaining foreliminating operation of cross talk in FIG. 21;

[0103]FIG. 23 is a diagram showing a first modified example of theeleventh embodiment in FIG. 20;

[0104]FIG. 24 is a diagram showing a second modified example of theeleventh embodiment in FIG. 20;

[0105]FIG. 25 is a view showing a schematic structure of a twelfthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0106]FIG. 26 is a schematic constitutional view of A-A′ sectioninvolving acoustic loudspeakers 2 a and 2 b in FIG. 25 viewed from adirection of the arrow;

[0107]FIG. 27 is a view showing a schematic structure of a thirteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0108]FIG. 28 is a side view showing the portable information terminalof FIG. 27;

[0109]FIG. 29 is a view showing a schematic structure of a fourteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0110]FIG. 30 is a diagram showing directivity of an acoustic soundspeaker array 2 s of FIG. 29;

[0111]FIG. 31 is a view showing a schematic structure of a fifteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0112]FIG. 32 is a view showing a schematic structure of a sixteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0113] FIGS. 33(a) and 33(b) are diagrams each explaining a circuitexample of signal processing for converging directivities of theacoustic loudspeakers 2 a and 2 b of FIG. 32;

[0114] FIGS. 34(a), 34(b), and 34(c) correspond to a first modifiedexample of the sixteenth embodiment of FIG. 32 and are diagrams forexplaining examples of signal processing wherein directivities ofacoustic loudspeakers 2 a and 2 b are allowed to be omnidirectional;

[0115]FIG. 35 is a view showing a schematic structure of a seventeenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0116]FIG. 36 is a view showing a schematic structure of an eighteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0117]FIG. 37 is a view indicating propagating directions of sounds fromthe portable information terminal 1 in FIG. 36;

[0118]FIG. 38 is a view showing a schematic structure of a nineteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention;

[0119]FIG. 39 is a view showing a first modified example of thenineteenth embodiment in FIG. 38;

[0120]FIG. 40 is a view showing a second modified example of thenineteenth embodiment in FIG. 38;

[0121]FIG. 41 is a view showing a third modified example of thenineteenth embodiment in FIG. 38;

[0122]FIG. 42 is a view showing a fourth modified example of thenineteenth embodiment in FIG. 38;

[0123]FIG. 43 is a view showing a fifth modified example of thenineteenth embodiment in FIG. 38;

[0124]FIG. 44 is a view showing a sixth modified example of thenineteenth embodiment in FIG. 38;

[0125]FIG. 45 is a view showing a schematic structure of a twentiethembodiment of a sound reproducing system in a portable informationterminal according to the present invention; and

[0126] FIG. 46 is a view showing a schematic structure of a twenty firstembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

THE BEST MODE FOR EXECUTING THE INVENTION

[0127] In the following, embodiments of the present invention will bedescribed by referring to the accompanying drawings.

[0128]FIG. 1 is a view showing a schematic structure of a firstembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0129] As shown in the present figure, a portable information terminal 1is composed of a screen display monitor 11 made of liquid crystal (LCD)for displaying menus, telephone numbers, functions and the like, a keypanel 12 for selecting a menu, input operation of a telephone number tobe operated, selecting operation of a function and the like operation,an ear piece 13 for hearing received voice through a loudspeaker, amouthpiece 14 for delivering voice to be transmitted to a microphone, anantenna 15 for transforming received radio waves into received signals,while transforming transmission signals into transmission radio waves,and the like components.

[0130] Furthermore, the portable information terminal 1 is provided withacoustic loudspeakers 2 a and 2 b for reproducing stereo sounds.

[0131] The acoustic loudspeakers 2 a and 2 b are disposed diagonally onthe front of the portable information terminal 1 at the opposite endsthereof along the longitudinal direction of the portable informationterminal. These acoustic loudspeakers 2 a and 2 b are directed to afrontward direction of the portable information terminal 1 in such thata distance defined between the acoustic loudspeakers 2 a and 2 b becomesthe maximum.

[0132]FIG. 2 is a diagram for explaining stereo sound reproduction ofthe acoustic loudspeakers 2 a and 2 b of FIG. 1.

[0133] As shown in the present figure, left (L) and right (R) signalsare reproduced stereophonically by means of the acoustic loudspeakers 2a and 2 b, and sounds thus reproduced stereophonically are delivered toa listener.

[0134] According to the above-described arrangement, it becomes possibleto reproduce sounds of comfortable and high acousticity by means of theacoustic loudspeakers 2 a and 2 b. Namely, unlike the prior art,reproduction of stereo sounds can be made by the use of only theportable information terminal 1 without accompanying headphone,earphone, external speaker system and the like.

[0135] In a first modified example of the first embodiment, a portableinformation terminal 1 is constituted in such that both backsides of theacoustic loudspeakers 2 a and 2 b are disengaged in the case when theportable information terminal 1 is disposed on a plane of desk, floor,by the wall or the like being in contact therewith, whereby reflectionof sounds can be utilized.

[0136] Since the portable information terminal 1 is compact,reproduction of low notes is difficult. According to the presentinvention, it becomes possible that when the portable informationterminal 1 is in contact with a plane of desk or the like, low notecomponents are reflected by the plane of desk to reverse a phasethereof, so that the low note components come to have the same phase asthat come out from the front of the acoustic loudspeakers 2 a and 2 b,whereby the low note components coming out frontward can be reinforced.

[0137] In the case where the portable information terminal 1 is not incontact with a plane of desk or the like, backsides of the acousticloudspeakers 2 a and 2 b are closed so as not to decrease sound pressureof low note components as a result of getting the low note componentsinto the front of the acoustic sound speakers 2 a and 2 b due todiffraction effects.

[0138] In a second modified example of the first embodiment, acousticloudspeakers 2 a and 2 b having high efficiency are used to operate thesame without employing any amplifier. Thus, since no amplifier isrequired as described above, the number of parts to be used in aportable information terminal 1 decreases, a compact and light-weightportable information terminal can be realized, and low power consumptioncan be realized, so that an available time by a single charge increasesin the portable information terminal 1.

[0139] In a third modified example of the first embodiment, it isconstituted in such that sounds can be reproduced at the same time ofphone call. In this case, acoustic sound reproducing signals aretransmitted in such a manner that they can be listened also by the otherparty during the phone call, whereby communication accompanied with BGMbecomes possible.

[0140] In a fourth modified example of the first embodiment, it isconstituted in such that individual sounds are reproduced by means ofacoustic loudspeakers 2 a and 2 b, respectively, and each sound volumeof individual sounds can be individually adjusted. Hence, when a foreignlanguage is learned, for example, while listening two languagesincluding native language, learning efficiency can be elevated bylistening a larger sound volume of the foreign language than that of thenative language.

[0141] FIGS. 3(a) and 3(b) are views each showing a schematic structureof a second embodiment of a sound reproducing system in a portableinformation terminal according to the present invention.

[0142] As shown in the present figure, a portable information terminal 1is an extensible type in comparison with the portable informationterminal of FIG. 1. Acoustic sound loudspeakers 2 a and 2 b are disposeddiagonally on the front of the portable information terminal 1 at theopposite ends thereof along the longitudinal direction of the portableinformation terminal.

[0143] As shown in FIGS. 3(a) and 3(b), when a flip section of theportable information terminal 1 is extended to broaden a distancebetween the acoustic loudspeakers 2 a and 2 b, and as a result, thedistance between the acoustic loudspeakers 2 a and 2 b becomes themaximum, whereby cross talk in the acoustic loudspeakers 2 a and 2 bdecreases.

[0144] Since the present invention has been applied to the extensibleportable information terminal, it becomes possible to provide stereosound reproduction of high acousticity in addition to convenience ofportage therefor in case of transfer.

[0145]FIG. 4 is a view showing a schematic structure of a thirdembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0146] As shown in the present figure, acoustic loudspeakers 2 a and 2 bare disposed on the front of the portable information terminal 1 at theopposite ends in the same side thereof along the longitudinal directionof the portable information terminal in comparison with the portableinformation terminal of FIG. 1, whereby it is arranged in such that adistance between the acoustic loudspeakers 2 a and 2 b becomes themaximum.

[0147] With respect to the present portable information terminal 1, itis supposed that the portable information terminal 1 is located on aplane of desk, floor or the like where is a lower position than that ofears of a listener, so that the acoustic loudspeakers 2 a and 2 b arearranged as described hereunder.

[0148]FIG. 5 is a sectional view taken along either the line Ba-Ba′ orthe line Bb-Bb′ of FIG. 4. As shown in the present figure, each of theacoustic loudspeakers 2 a and 2 b is disposed at a certain angle withrespect to a cabinet wall of the portable information terminal 1 whereinthe acoustic loudspeakers 2 a and 2 b are to be located, respectively,so that sounds from both the acoustic loudspeakers 2 a and 2 b reach aposition 5 of the listener along a direction 7 of propagation of sounds.

[0149] It is to be understood that an angle defined between either ofthe acoustic loudspeakers 2 a and 2 b and a corresponding cabinet wallas well as an angle defined between the acoustic loudspeakers 2 a and 2b may be freely altered.

[0150] As mentioned above, when each direction of the acousticloudspeakers 2 a and 2 b is directed to a position of the listener,sounds, which can be more easily listen by the listener, can berealized.

[0151]FIG. 6 is a view showing a schematic structure of a fourthembodiment of a sound reproducing system in a portable informationterminal according to the present invention, and FIG. 7 is a sectionalview taken along the line B-B′ of FIG. 6.

[0152] As shown in FIG. 6, when compared with FIG. 4, although acousticloudspeakers 2 a and 2 b are disposed on the front of the portableinformation terminal 1 at the opposite ends in the same side thereofalong the longitudinal direction of the portable information terminal asin the case of FIG. 4, the acoustic loudspeakers 2 a and 2 b aredisposed outwards to each other as shown in FIG. 7.

[0153] In this case, it is to be understood that the outward angles withrespect to both the acoustic loudspeakers 2 a and 2 b may be freelychanged.

[0154] It is supposed herein that further downsizing of the portableinformation terminal 1 results in a narrower distance between theacoustic loudspeakers 2 a and 2 b. As a result, cross talk increasesbetween the acoustic loudspeakers 2 a and 2 b, so that stereophoniceffects disappear. However, when the acoustic loudspeakers 2 a and 2 bare located outwards, respectively, as shown in FIG. 6, the cross talkdecreases as described hereinafter.

[0155] FIGS. 8(a) and 8(b) are diagrams each explaining for decrease incross talk of acoustic loudspeakers 2 a and 2 b shown in FIGS. 6 and 7.

[0156] In case of FIG. 8(a), acoustic loudspeakers 2 a and 2 b aredisposed in the same direction with respect to a listener. In this case,a propagating direction 7 a of sounds from the acoustic loudspeaker 2 ais composed of a propagating direction 7 aL towards a left ear of thelistener and a propagating direction 7 aR towards a listener's right earas cross talk (dotted line), while a propagating direction 7 b of soundsfrom the acoustic loudspeaker 2 b is composed of a propagating direction7 bL towards a listener's left ear as cross talk (dotted line) and apropagating direction 7 bR towards a listener's right ear.

[0157] There is no cross talk unlike the above-described situation whenheadphone or earphone is used, because sounds do not propagate in space.

[0158] When a distance between the acoustic loudspeakers 2 a and 2 b ismaintained at more than a certain distance, a sound pressure and a phasedifference produced in both ears of a listener, respectively, fromsounds in the propagating directions 7 aL and 7 aR as well as sounds inthe propagating directions 7 bR and 7 bL, which are delivered from theacoustic loudspeakers 2 a and 2 b, are extensive, and further,polarities thereof are mutually inverse, so that sound sources producedby the acoustic loudspeakers 2 a and 2 b are discriminated.

[0159] In this respect, however, when the acoustic loudspeakers 2 a and2 b approach to each other, sounds in the propagating directions 7 bRand 7 aR reach the listener's right ear, while sounds in the propagatingdirections 7 aL and 7 bL reach the listener's left ear in a situationwherein a sound pressure and a phase difference produced in both theears of the listener based on acoustic waves transmitted from theacoustic loudspeakers 2 a and 2 b are small. Thus, stereo sound effectsdisappear, and only monaural effects are obtained.

[0160] As shown in FIG. 8(b), when the acoustic loudspeakers 2 a and 2 bare disposed outwards with respect to each other, a ratio of sounds,which are those in the propagating direction 7 aR towards a listener'sright ear from the acoustic loudspeaker 2 a do not reach the listener'sright ear, as well as a ratio of sounds, which are those in thepropagating direction 7 bL towards a listener's left ear from theacoustic loudspeaker 2 b do not reach the listener's left ear, increase,so that cross talk decreases.

[0161] Because of such decrease in cross talk, a ratio of sounds, whichreach the listener's right ear from the acoustic loudspeaker 2 b, aswell as a ratio of sounds, which reach the listener's left ear from theacoustic loudspeaker 2 a, increase.

[0162] For this reason, the listener can discriminate sound sources ofthe acoustic loudspeakers 2 a from that of the acoustic loudspeakers 2b, so that it becomes possible to obtain stereo sound effects as in thecase of headphone or earphone, even if a distance between the acousticloudspeakers 2 a and 2 b becomes narrow.

[0163]FIG. 9 is a view showing a schematic structure of a fifthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0164] As shown in the present figure, in comparison with FIG. 1, anacoustic loudspeaker 2 a is disposed on the front of a portableinformation terminal 1 in such a manner that the loudspeaker 2 a extendsto the left side of the portable information terminal viewed from thetop and the front thereof, while the acoustic loudspeaker 2 b isdisposed on the front of the portable information terminal 1 in such amanner that the loudspeaker 2 b extends to the left side of the portableinformation terminal viewed from the bottom and the front thereof.

[0165] According to the present invention, it is constituted in suchthat propagating directions of sounds from acoustic loudspeakers 2 a and2 b are directed to a listener in a situation wherein a portableinformation terminal 1 is located on a plane of desk, floor or the like,which is positioned at a lower position than ears of the listener asshown in FIG. 4 in addition to stereo sound reproduction of highacousticity derived from effects of decrease in cross talk as describedin FIGS. 7 and 8. As a result, sounds can be more easily listened basedon the above-described constitution.

[0166]FIG. 10 is a view showing a schematic structure of a sixthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0167] As shown in the present figure, in comparison with FIG. 1, aportable information terminal 1 is a foldaway type wherein an acousticloudspeaker 2 a is disposed on the front of a portable informationterminal 1 in such a manner that the loudspeaker 2 a extends to the leftside of the portable information terminal viewed from the top and thefront thereof, while the acoustic loudspeaker 2 b is disposed on thefront of the portable information terminal 1 in such a manner that theloudspeaker 2 b extends to the left side of the portable informationterminal viewed from the bottom and the front thereof.

[0168] As compared with an example shown in FIG. 9, the presentinvention has been applied to the foldaway portable information terminal1 in the sixth embodiment, so that it becomes possible to provide stereosound reproduction of high acousticity in addition to convenience ofportage in case of transfer.

[0169] Although it is desired that a distance defined between bothacoustic loudspeakers is broad, dimensions of a distance betweenindividual acoustic loudspeakers and the like are self-limited due to asize of the portable information terminal 1, a configuration of otherparts in such portable information terminal aiming to downsize andreduce its weight. A further explanation will be made as to the case asdescribed herein.

[0170]FIG. 11 is a view showing a schematic structure of a seventhembodiment of a sound reproducing system in a portable informationterminal according to the present invention, and FIG. 12 is a schematicconstitutional view of A-A′ section involving acoustic loudspeakers 2 aand 2 b in FIG. 11 viewed from a direction of the arrow.

[0171] As shown in the present figure, in comparison with FIG. 1,acoustic loudspeakers 2 a and 2 b are disposed on the front of aportable information terminal 1 in such that both surfaces of theacoustic loudspeakers 2 a and 2 b coincide with a surface of theportable information terminal 1, these loudspeakers 2 a and 2 b arealigned horizontally, they are located to be directed frontwards withrespect to the portable information terminal 1, and they are positionedbetween a screen display monitor 11 and a key panel 12.

[0172] A cross talk barrier 8 is disposed between the acousticloudspeakers 2 a and 2 b, and the cross talk barrier 8 is a wall, whichprojects outside surfaces of the acoustic loudspeakers 2 a and 2 b. Thecross talk barrier 1 reduces cross talk appearing between the acousticloudspeakers 2 a and 2 b in the case where both the acousticloudspeakers 2 a and 2 b are positioned to be close to each other asdescribed above, whereby stereo sound reproduction of high acousticityis realized.

[0173] FIGS. 13(a) and 13(b) are diagrams each explaining for decreasein cross talk of acoustic loudspeakers 2 a and 2 b shown in FIGS. 11 and12.

[0174] As shown in FIG. 13(b), cross talk 7 aR, 7 bL between theacoustic loudspeakers 2 a and 2 b is physically blocked off by means ofthe cross talk barrier 8, so that the cross talk does not reach bothleft and right ears of a listener. As a result, it becomes possible torealize stereo sound reproduction of high acousticity.

[0175] Since the cross talk barrier 8 protrudes from the portableinformation terminal 1, there is a possibility of arising a trouble ofbeing hooked by something in case of moving the portable informationterminal 1. In this respect, it is constituted in such that the crosstalk barrier 8 is made to be transferable, for example, it may befolded, or it may be removed in case of nonuse, while the cross talkbarrier 8 is to be set in only the case where sounds are to be listenedin a first modified example in the seventh embodiment of the presentinvention.

[0176] According to the arrangement as described above, there is notrouble of damage or the like in case of transfer of the portableinformation terminal, while it becomes possible to reproduce stereosounds of high acousticity in case of listening sounds.

[0177] It may be constituted that a length of the cross talk barrier 8extends in a vertical direction of the portable information terminalshown in FIG. 11. When the cross talk barrier 8 is short in a verticaldirection of the portable information terminal, cross talk can beavoided where the barrier exists, but a factor for cross talk appears ata position where no barrier exists. In this respect, however, when thecross talk barrier 8 is extended in a vertical direction, it becomespossible to decrease further cross talk.

[0178] Furthermore, when it is constituted in such that a storage spacefor the cross talk barrier 8 is defined in the portable informationterminal 1, and the cross talk barrier 8 disengaged is contained in thestorage space, it becomes possible to avoid missing for the cross talkbarrier 8.

[0179]FIG. 14 is a diagram showing a second modified example of aschematic structure of the seventh embodiment in FIG. 11.

[0180] As shown in the present figure, acoustic loudspeakers 2 a and 2 bare disposed at more fallen positions than a position of cabinet wall 6of a portable information terminal 1 in a constitution in a sectioncorresponding to the line A-A′ of FIG. 11, and the acoustic loudspeaker2 a is separated from the acoustic loudspeaker 2 b by means of aboundary 8′.

[0181] The boundary 8′ results in a similar effect as that of the crosstalk barrier 8 proposed in the embodiment of FIGS. 11 and 12, and thus,in other words, a cross talk barrier, which does not protrude theoutside, can be realized, while it becomes possible to realize stereosound reproduction of high acousticity in case of listening sounds.

[0182]FIG. 15 is a diagram showing a third modified example of aschematic structure of the seventh embodiment in FIG. 11.

[0183] As shown in the present figure, acoustic loudspeakers 2 a and 2 bare located at more fallen positions than a position of a cabinet wallof portable information terminal 1, respectively. A cross talk barrier 8prevents cross talk of sounds appeared between the acoustic loudspeakers2 a and 2 b. In general, the higher height of the cross talk barrier 8results in the more intensive effect, but when it projects from acabinet wall position 6 of the portable information terminal 1,resulting in a possibility of troubles.

[0184] For this reason, when a cross talk barrier 8 is provided withrespect to acoustic loudspeakers 2 a and 2 b, which have been situatedin a fallen state as described above, an amount of projectioncorresponding to a depth of depression decreases. Thus, when comparedwith such a case where acoustic loudspeakers 2 a and 2 b are disposedclosely to a cabinet wall position 6 of the portable informationterminal 1 and no depression is defined (FIG. 12) on the cabinet wallposition 6, a cross talk barrier 8, which decreases a portion protrudingthe outside, can be realized. On one hand, it becomes possible toreproduce stereo sounds of high acousticity.

[0185]FIG. 16 is a view showing a schematic structure of an eighthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0186] As shown in the present figure, in comparison with FIG. 1, anacoustic loudspeaker 2 a is disposed in such that it protrudes from aleft side of a portable information terminal 1 viewed from the frontthereof, and the acoustic loudspeaker 2 a is situated so as to directfrontward of the portable information terminal 1, while an acousticloudspeaker 2 b protrudes from a right side of the portable informationterminal 1 viewed from the front thereof, and it is situated so as todirect frontward of the portable information terminal 1.

[0187] The acoustic loudspeakers 2 a and 2 b are disposed on a cabinetwall of the portable information terminal 1 at an angle of substantiallyninety degrees at the position disposed. When the acoustic loudspeakers2 a and 2 b are disposed on sides of the portable information terminal 1in a state wherein they are protruded as described above, a distancebetween the acoustic loudspeakers 2 a and 2 b broadens as compared withan example of the sixth embodiment of the present invention shown inFIG. 11. Accordingly, cross talk arising from the acoustic loudspeakers2 a and 2 b can be decreased without employing the cross talk barrier 8,so that it becomes possible to reduce the number of parts to be used,and further to reproduce stereo sounds of high acousticity.

[0188] Moreover, when the acoustic loudspeakers 2 a and 2 b are disposedon the portable information terminal 1 at positions where there aredeeper than that of the above-described examples along the directionextending from the front to the back of the portable informationterminal 1, the portable information terminal itself functions as across talk barrier for the acoustic loudspeakers 2 a and 2 b. Thus,cross talk of sounds produced from the acoustic loudspeakers 2 a and 2 bcan be reduced, whereby reproduction of stereo sounds of highacousticity can be realized.

[0189] As mentioned above, an angle defined by the acoustic loudspeakers2 a and 2 b and a cabinet wall may be freely changed.

[0190] Furthermore, since the acoustic loudspeakers 2 a and 2 b havebeen protruded from the portable information terminal 1, there is apossibility of troubles in case of carrying such portable informationterminal. In this respect, the acoustic loudspeakers 2 a and 2 b aremade to be capable of being contained in a cabinet of the portableinformation terminal 1 as a modified example of the eighth embodiment,and the acoustic loudspeakers 2 a and 2 b are arranged to be pull-outtype, which can be pulled out from the cabinet in use of the portableinformation terminal 1. Thus, it becomes possible to avoid troubles asto protruded acoustic loudspeakers 2 a and 2 b in case of carrying theportable information terminal 1.

[0191]FIG. 17 is a view showing a schematic structure of a ninthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0192] As shown in the present figure, in comparison with FIG. 11, anacoustic loudspeaker 2 a is disposed in such that it protrudes from aleft side of a portable information terminal 1 viewed from the frontthereof, and the acoustic loudspeaker 2 a is situated so as to directfrontward of the portable information terminal 1, while an acousticloudspeaker 2 b protrudes from a right side of the portable informationterminal 1 viewed from the front thereof, and it is situated so as todirect frontward of the portable information terminal 1.

[0193] Moreover, each of the acoustic loudspeakers 2 a and 2 b islocated at a position where there is somewhat deeper from the front ofthe portable information terminal 1. Such a cabinet wall residing on thefront of the acoustic loudspeaker 2 a or 2 b at a position where itintercepts the acoustic loudspeakers 2 a and 2 b is removed further fromthat of the seventh embodiment of the present invention mentioned inFIG. 16, whereby a vibrating surface of the acoustic loudspeaker 2 a or2 b is not covered by the cabinet wall. For this reason, sounds fromboth the fronts of the acoustic loudspeakers 2 a and 2 b are deliveredto a listener, whereby a sound pressure can be more elevated.

[0194] In the present example, since the acoustic loudspeakers 2 a and 2b are not allowed to protrude from the front of the portable informationterminal 1, the portable information terminal 1 main body existingbetween the acoustic loudspeakers 2 a and 2 b functions as a cross talkbarrier between both the loudspeakers, so that it becomes possible toreproduce stereo sounds of higher acousticity.

[0195] On the other hand, when the acoustic loudspeakers 2 a and 2 bhave been protruded from the portable information terminal 1 asmentioned above, there is a possibility of troubles in case of carryingsuch portable information terminal. In this respect, the acousticloudspeakers 2 a and 2 b are made to be capable of being contained in acabinet of the portable information terminal 1 as a modified example ofthe ninth embodiment, and the acoustic loudspeakers 2 a and 2 b arearranged to be pull-out type, which can be pulled out from the cabinetin use of the portable information terminal 1. Thus, it becomes possibleto avoid troubles as to the protruded acoustic loudspeakers 2 a and 2 bin case of carrying the portable information terminal 1.

[0196]FIG. 18 is a view showing a schematic structure of a tenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0197] As shown in the present figure, in comparison with FIG. 11, anacoustic loudspeaker 2 a is disposed on the front of a portableinformation terminal 1 in such a manner that the loudspeaker 2 a extendsto the left side of the portable information terminal viewed from thefront thereof, while the acoustic loudspeaker 2 b is disposed on thefront of the portable information terminal 1 in such a manner that theloudspeaker 2 b extends to the left side of the portable informationterminal viewed from the front thereof.

[0198] In the present invention, in comparison with an example of FIG.16, since the acoustic loudspeakers 2 a and 2 b do not protrude from acabinet wall, the acoustic loudspeakers 2 a and 2 b do not result introubles, so that a situation wherein these acoustic loudspeakers 2 aand 2 b are hooked by something can be avoided.

[0199] Furthermore, when the acoustic loudspeakers 2 a and 2 b arelocated outwards mutually to each other, cross talk in sounds from theacoustic loudspeakers 2 a and 2 b become slight, so that it becomespossible to realize reproduction of stereo sounds of higher acousticity.

[0200]FIG. 19 is a view showing a schematic structure of a eleventhembodiment of a sound reproducing system in a portable informationterminal according to the present invention, and FIG. 20 is a schematicconstitutional view of A-A′ section involving acoustic loudspeakers 2 aand 2 b in FIG. 19 viewed from a direction of the arrow.

[0201] As shown in the present figure, in comparison with FIG. 1,acoustic loudspeakers 2 a and 2 b are disposed on the front of aportable information terminal 1 in such that both surfaces of theacoustic loudspeakers 2 a and 2 b coincide with a surface of theportable information terminal 1, these loudspeakers 2 a and 2 b arealigned horizontally, and they are positioned between a screen displaymonitor 11 and a key panel 12.

[0202] In the present embodiment, since no cross talk barrier 8 of FIG.11 is provided, the following signal processing for eliminating crosstalk is made in place of provision of the cross talk barrier 8.

[0203]FIG. 21 is a schematic diagram showing a circuit for executingsignal processing of cross talk elimination. As shown in the presentfigure, inverse filters 20 a and 20 b are provided for inputting branchsignals of left (L) and right (R) signals to the acoustic loudspeakers 2a and 2 b.

[0204] The inverse filters 20 a and 20 b invert each phase of inputbranch signals. An adder 21 a is disposed between a branch point of theright (R) signals and the acoustic loudspeaker 2 a, while an adder 21 bis disposed between a branch point of the left (L) signals and theacoustic loudspeaker 2 b. The adder 21 a adds the right (R) signals tooutput signals of the inverse filter 20 a to output the resultingsignals to the acoustic loudspeaker 2 a, while the adder 21 b adds theleft (L) signals to output signals of the inverse filter 20 b to outputthe resulting signals to the acoustic loudspeaker 2 b.

[0205] FIGS. 22(a) and 22(b) are schematic diagrams each explaining foreliminating operation of cross talk in FIG. 21. As shown in FIG. 22(a),cross talks 7 aR and 7 bL are involved in sounds from acousticloudspeakers 2 a and 2 b to a listener in propagating directions 7 a and7 b, respectively, as mentioned above.

[0206] As shown in FIG. 22(b), when signal processing for cross talk ismade, sounds as cross talks in the propagating directions 7 aR and 7 bLare cancelled by sounds, which have been phase-inverted, so that thecross talks are eliminated.

[0207]FIG. 23 is a diagram showing a first modified example of theeleventh embodiment in FIG. 20.

[0208] As shown in the present figure, each of the acoustic loudspeakers2 a and 2 b is located at a position that is further fallen than acabinet wall 6 of a portable information terminal 1. Hence, a key panelor the like may be placed on a part or the whole of the cabinet wall 6of the portable information terminal 1 corresponding to a surface onwhich the acoustic loudspeakers 2 a and 2 b have been disposed, so thatefficient arrangement of parts can be made in the portable informationterminal 1.

[0209]FIG. 24 is a diagram showing a second modified example of theeleventh embodiment in FIG. 20.

[0210] As shown in the present figure, when acoustic loudspeakers 2 aand 2 b are partially protruded from a cabinet of a portable informationterminal 1, an internal space of the cabinet corresponding to aprotruded portion is saved, so that other parts may be disposed in theinternal space thus saved, or the whole cabinet can be downsized,whereby it is possible to realize a more compact and weight-savedportable information terminal 1.

[0211]FIG. 25 is a view showing a schematic structure of a twelfthembodiment of a sound reproducing system in a portable informationterminal according to the present invention, and FIG. 26 is a schematicconstitutional view of A-A′ section involving acoustic loudspeakers 2 aand 2 b in FIG. 25 viewed from a direction of the arrow.

[0212] As shown in the present figures, in comparison with FIG. 19,acoustic loudspeakers 2 a and 2 b extend to a part of a key panel 12 andare disposed inside a cabinet of the portable information terminal 1 ina fallen state. Thus, a ratio of area occupied by the acousticloudspeakers is reduced with respect to a portable information terminal1. According to such constitution as described above, a cabinet wall ofthe portable information terminal can be utilized for other useapplication such as a key panel, whereby downsizing of portableinformation terminal can be realized.

[0213] Moreover, it is arranged in such that the acoustic loudspeakers 2a and 2 b are covered with a perforated section 6′ of a cabinet wall, sothat sounds are propagated through the perforated section 6′ of thecabinet wall, whereby a sufficient sound pressure is obtained.

[0214] Furthermore, cross talk in the acoustic loudspeakers 2 a and 2 bis eliminated by means of the signal processing circuit of FIG. 21.Hence, it becomes possible to realize reproduction of stereo sounds ofhigh acousticity can be realized with a sufficient sound pressure incase of listening sounds.

[0215]FIG. 27 is a view showing a schematic structure of a thirteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention, and FIG. 28 is a side viewshowing the portable information terminal of FIG. 27.

[0216] As shown in the present figures, in comparison with FIG. 4,acoustic loudspeakers 2 a and 2 b are located frontwards with respect tothe portable information terminal 1 at the opposite ends in the sameside thereof along the longitudinal direction of the portableinformation terminal 1, while an acoustic loudspeaker 2 c is locatedrearwards with respect to the portable information terminal 1 at acentral part along the longitudinal direction thereof. Namely, theacoustic loudspeaker 2 c is placed so as to have an angle of 180 degreeswith respect to acoustic loudspeakers 2 a and 2 b.

[0217] To the acoustic loudspeakers 2 a and 2 b, characteristics, whichare specialized to middle- to high-pitched tone ranges, are given, whilea characteristic, which is specialized to low-pitched tone range, isgiven to the acoustic loudspeaker 2 c, whereby it is allowed to functionas a woofer, so that it becomes possible to reproduce sounds of higheracousticity in broadband.

[0218] Moreover, it is constituted in such that directions of theacoustic loudspeakers 2 a, 2 b, and 2 c are movable as a modifiedexample of the twelfth embodiment of the present invention.

[0219] For instance, when the portable information terminal 1 is placedat a low position, the acoustic loudspeakers 2 a, 2 b, and 2 c are setupwards. On one hand, when sounds spreading a wide area are desired toacquire, for example, when sounds are desired to be listened by manypersons, the acoustic loudspeakers are set outwards so as to be easilylistened. As described above, according to the present modification, itis possible to select optimum directions for speakers as the case maybe, whereby versatility can be elevated.

[0220]FIG. 29 is a view showing a schematic structure of a fourteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0221] As shown in the present figure, an acoustic loudspeaker array 2 sis disposed on a portable information terminal 1 wherein the acousticloudspeaker array 2 s is an alignment of a plurality of acousticloudspeakers being aligned rearwards with respect to the portableinformation terminal 1 in a row along the longitudinal direction of theportable information terminal 1.

[0222]FIG. 30 is a diagram showing directivity of an acoustic soundspeaker array 2 s of FIG. 29. As shown in the present figure,directivity is improved in a direction of the acoustic loudspeaker array2 s. In the case where sounds are listened by a small number oflisteners by means of the present portable information terminal 1 in aplace such as coffee house, it is possible to arrange in such thatsounds are delivered to only the listeners, but not the third party, sothat listening of sounds in which harassment with respect to asurrounding area can be avoided without employing headphone and thelike.

[0223]FIG. 31 is a view showing a schematic structure of a fifteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0224] As shown in the present figure, in comparison with FIG. 1,acoustic loudspeakers 2 a, 2 b, 2 c, and 2 d are disposed around aportable information terminal 1. As described above, when the acousticloudspeakers 2 a, 2 b, 2 c, and 2 d are placed all around, moreeffective omnidirectional effect can be elevated. Thus, it is convenientfor such a case where sounds are listened by a large number of persons.

[0225] In the following, an example wherein a directivity of acousticsound propagation is converged to a certain direction, and an examplewherein acoustic sound propagation is allowed to more widely expand, inother words, it makes to be omnidirectional will be described.

[0226]FIG. 32 is a view showing a schematic structure of a sixteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0227] As shown in the present figure, in comparison with FIG. 29, onlytwo acoustic loudspeakers 2 a and 2 b are disposed at opposite ends ofthe portable information terminal 1 in the longitudinal directionthereof in such a manner that they are located rearwards with respect tothe portable information terminal 1. Directivities of acoustic soundpropagation of the acoustic loudspeakers 2 a and 2 b are converged to acertain direction by means of signal processing as described hereunder.

[0228] FIGS. 33(a) and 33(b) are diagrams each explaining a circuitexample of signal processing for converging directivities of theacoustic loudspeakers 2 a and 2 b of FIG. 32.

[0229] As shown in FIG. 33(a), a delay means 22 is disposed to an inputside of, for example, the acoustic loudspeaker 2 b between the acousticloudspeakers 2 a and 2 b.

[0230] It is supposed that directivity is converged in a direction ofacoustic sound propagation indicated by dotted lines in the acousticloudspeakers 2 a and 2 b in the case where no delay means 22 isprovided.

[0231] In the case where the delay means 22 is provided, a right (R)signal is more delayed than a left (L) signal, so that a directivity ofsounds produced by the acoustic loudspeakers 2 a and 2 b is convergedfrom the case where no delay exists to the case where the delay ispresent as shown in FIG. 33(a).

[0232] In this respect, when an arbitrary amount of delay is set, itbecomes possible to converge arbitrarily a direction of directivity insounds.

[0233] As shown in FIG. 33(b), an attenuator 23 is disposed on an inputside of, for example, the acoustic loudspeaker 2 b between the acousticloudspeakers 2 a and 2 b.

[0234] In the case where no attenuator 23 exists, it is considered thatdirectivity is converged in a propagating direction of sounds indicatedby dotted lines in the acoustic loudspeakers 2 a and 2 b.

[0235] By means of the attenuator 22, right (R) signal comes to have asmaller amplitude than that of left (L) signal, whereby directivity ofsounds produced by the acoustic loudspeakers 2 a and 2 b is convergedtowards a direction of the case where there is no attenuation to thecase where there is an attenuation as shown in FIG. 33(a).

[0236] Accordingly, when an arbitrary amount of attenuation is set, itbecomes possible to converge arbitrarily a direction of directivity insounds.

[0237] As described above, since directivity can be converged to acertain direction, it is possible to maintain such a situation thatsounds are delivered to only a small number of listeners in case oflistening such sounds in a coffee shop or the like by a small number ofthese listeners, but not delivered to the third party. Thus, it ispossible to listen sounds by a small number of acoustic loudspeakerswithout accompanying harassment to a surrounding area with no use ofheadphones, earphones, and the like.

[0238] FIGS. 34(a), 34(b), and 34(c) correspond to a first modifiedexample of the sixteenth embodiment of FIG. 32 and are diagrams forexplaining circuit examples of signal processing wherein directivitiesof acoustic loudspeakers 2 a and 2 b are allowed to be omnidirectional.

[0239] As shown in the present figures, a delay means 24 a for branchingleft (L) signals to delay the same and an adder 25 a for adding signalsthus delayed by the delay means 24 a to the original left (L) signals tooutput the same to an acoustic loudspeaker 2 a are disposed on an inputside of the acoustic loudspeaker 2 a.

[0240] Furthermore, a delay means 24 b for branching right (R) signalsto delay the same and an adder 25 b for adding signals thus delayed bythe delay means 24 b to the original right (R) signals to output thesame to an acoustic loudspeaker 2 b are disposed on an input side of theacoustic loudspeaker 2 b.

[0241] A propagating direction of sounds produced by the acousticloudspeakers 2 a and 2 b in the case where there is no delay in bothleft (L) and right (R) signals corresponds to a direction (a) as shownin the present figures.

[0242] A propagating direction of sounds produced by the acousticloudspeakers 2 a and 2 b in the case where there is a delay in right (R)signals, while there is no delay in left (L) signals corresponds to adirection (b) as shown in the present figures.

[0243] A propagating direction of sounds produced by the acousticloudspeakers 2 a and 2 b in the case where there is no delay in right(R) signals, while there is a delay in left (L) signals corresponds to adirection (c) as shown in the present figures.

[0244] A propagating direction of sounds produced through the acousticloudspeakers 2 a and 2 b in the case where there is a delay in right (R)signals and there is also a delay in left (L) signals corresponds to adirection (a) as shown in the present figures, if both amounts of delayare equal to each other.

[0245] As mentioned above, when acoustic loudspeakers are disposed onlyeither side of a portable information terminal 1 in the case wheresounds are listened from the portable information terminal 1 positionedat the center of a surrounding circle by listeners situated on thecircle, it is anticipated that listening of sounds becomes difficult ona side where no acoustic loudspeaker is provided.

[0246] However, according to signal processing of the present invention,omnidirectional effect wherein propagation of sounds is more widelyexpanded is realized, whereby listening of sounds with a single portableinformation terminal 1 becomes possible by a number of listeners withoutadding any acoustic loudspeaker.

[0247] While one each of delay means have been disposed on input sidesof the acoustic loudspeakers 2 a and 2 b, the invention is not limitedthereto, but a plurality of delay means each having a different delayamount my be provided. As a result, more smooth omnidirectional effectcan be realized. In addition, when the number of loudspeakers isincreased, broader listening of sounds becomes possible.

[0248] According to the time and circumstances, the number of listenersand a place where sounds to be listened change, so that if functions forthe above described signal processing is simple, there is a case wheredisadvantages arise.

[0249] In order to avoid such disadvantages, countermeasures thereforwill be described hereunder.

[0250]FIG. 35 is a view showing a schematic structure of a seventeenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0251] As shown in the present figure, a directional processing sectionfor converging signals 31, an omnidirectional signal processing section32, and a switching section 33 are disposed on an input side of acousticloudspeakers 2 a and 2 b.

[0252] The directional processing section for converging signals 31 hasa constitution as shown in FIG. 33 and executing signal processing forconverging directivity in a certain direction.

[0253] The omnidirectional signal processing section 32 has aconstitution as shown in FIGS. 34(a), 34(b), and 34(c) and executingsignal processing for producing an omnidirectional condition.

[0254] The switching section 33 selects alternatively the directionalprocessing section for converging signals 31 or the omnidirectionalsignal processing section 32.

[0255] As described above, since signal-processing functions are made tobe selectable, optimum signal processing can be made according tocircumstances; besides, comfortable listening of sounds becomes alwayspossible.

[0256]FIG. 36 is a view showing a schematic structure of an eighteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0257] As shown in the present figure, in comparison with FIG. 1,acoustic loudspeakers 2 a and 2 b are disposed horizontally on the upperpart of a portable information terminal 1 wherein the acousticloudspeaker 2 a directs frontwards from the portable informationterminal 1, while the acoustic loudspeaker 2 b directs rearwards fromthe portable information terminal 1, whereby they direct differentdirections at an angle of 180 degrees one another.

[0258]FIG. 37 is a view indicating propagating directions of sounds fromthe portable information terminal 1 in FIG. 36. As shown in the presentfigure, positions 5 a and 5 b for listening sounds are those at whichsounds delivered from the acoustic loudspeakers 2 a and 2 b are to belistened. Propagating directions 7 a and 7 b of sounds indicatepropagating directions of those produced from the acoustic loudspeakers2 a and 2 b.

[0259] From the acoustic loudspeakers 2 a and 2 b, individuallydifferent sounds, for example voices of two different languages arelistened by a plurality of persons. In this case, for instance, personswho wish to listen a language from the acoustic loudspeaker 2 a may hearthe language at the position 5 a for listening sounds, while persons whowish to listen another language from the acoustic loudspeaker 2 b mayhear the language at the position 5 b for listening sounds. As a result,it becomes possible to listen a plurality of languages at the same timeby the use of a single portable information terminal 1.

[0260] Furthermore, when the acoustic loudspeakers 2 a and 2 b aredisposed on both the surfaces of the portable information terminal 1, aneffect for making sounds omnidirectional is also obtained. Hence, in thecase where sounds are listened from the portable information terminal 1positioned at the center of a surrounding circle by listeners situatedon the circle, it becomes possible to listen sounds by a number ofpersons with the use of a single portable information terminal 1.

[0261] For instance, when sounds are listened in a condition asdescribed above in case of outing, such purpose can be achieved by asingle portable information terminal 1, so that there is no need fortaking other external loudspeakers or the like with the portableinformation terminal 1. Thus, reduction of baggage becomes possible,besides such a situation that one neglects to bring a sound reproducingsystem with him (or her) can be avoided, because such portableinformation terminal 1 is usually carried by a user in case of outing.

[0262]FIG. 38 is a view showing a schematic structure of a nineteenthembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0263] As shown in the present figure, in comparison with FIG. 1, anacoustic sound loud speaker 2, and an acoustic loudspeaker serving alsoas speaking microphone 42 are disposed on a portable informationterminal 1.

[0264] As described above, when an acoustic loudspeaker is used also asa speaking microphone, the number of parts to be used in a portableinformation terminal is reduced, so that downsizing and weight reductionof the portable information terminal can be realized.

[0265]FIG. 39 is a view showing a first modified example of thenineteenth embodiment in FIG. 38.

[0266] As shown in the present figure, an acoustic sound loud speaker 2,and an acoustic loudspeaker serving also as receiving speaker 43 aredisposed on a portable information terminal 1.

[0267] As described above, when an acoustic loudspeaker is used also asa receiving speaker, the number of parts to be used in a portableinformation terminal is reduced, so that downsizing and weight reductionof the portable information terminal can be realized.

[0268]FIG. 40 is a view showing a second modified example of thenineteenth embodiment in FIG. 38.

[0269] As shown in the present figure, an acoustic loudspeaker servingalso as speaking microphone 42, and an acoustic loudspeaker serving alsoas receiving speaker 43 are disposed on a portable information terminal1.

[0270] As described above, when an acoustic loudspeaker is used aseither a speaking microphone, or a receiving speaker, the number ofparts to be used in a portable information terminal is reduced, so thatdownsizing and weight reduction of the portable information terminal canbe realized.

[0271]FIG. 41 is a view showing a third modified example of thenineteenth embodiment in FIG. 38.

[0272] As shown in the present figure, an acoustic sound loud speaker 2,and an acoustic loudspeaker serving also as a ringer 44 for soundingincoming sounds are disposed on a portable information terminal 1.

[0273] As described above, when an acoustic loudspeaker is used also asa ringer, the number of parts to be used in a portable informationterminal is reduced, so that downsizing and weight reduction of theportable information terminal can be realized.

[0274]FIG. 42 is a view showing a fourth modified example of thenineteenth embodiment in FIG. 38.

[0275] As shown in the present figure, an acoustic loudspeaker 2, and anacoustic loudspeaker serving also as a vibrator for vibrating to notifyincoming signals 45 are disposed on a portable information terminal 1.

[0276] As described above, when an acoustic loudspeaker is used also asa vibrator, the number of parts to be used in a portable informationterminal is reduced, so that downsizing and weight reduction of theportable information terminal can be realized.

[0277]FIG. 43 is a view showing a fifth modified example of thenineteenth embodiment in FIG. 38.

[0278] As shown in the present figure, an acoustic loudspeaker 2, and anacoustic loudspeaker serving also as a screen display monitor 46 aredisposed on a portable information terminal 1.

[0279] As described above, when an acoustic loudspeaker is used also asa screen display monitor, the number of parts to be used in a portableinformation terminal is reduced, so that downsizing and weight reductionof the portable information terminal can be realized.

[0280]FIG. 44 is a view showing a sixth modified example of thenineteenth embodiment in FIG. 38.

[0281] As shown in the present figure, an acoustic loudspeaker 2, and anacoustic loudspeaker serving also as a key panel 47 are disposed on aportable information terminal 1.

[0282] As described above, when an acoustic loudspeaker is used also asa key panel, the number of parts to be used in a portable informationterminal is reduced, so that downsizing and weight reduction of theportable information terminal can be realized.

[0283] As to sound data reproduced in the above description, when sounddata is handled in such that the one stored in a built-in memory, mediumor the like housed in a portable information terminal 1 is reproduced,or sound data stored at the same time of reception from an externalsource such as a download site, and a personal computer (PC) isreproduced, the portable information terminal 1 is considered to have aconstitution functioning as a sound source and also as an acousticloudspeaker. According to such constitution, sound data is limited, andtherefore, an available range for sound data is intended to expand asdescribed hereinafter.

[0284]FIG. 45 is a view showing a schematic structure of a twentiethembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0285] As shown in the present figure, in comparison with FIG. 40, asignal input terminal 50 is provided on a portable information terminal1, and an acoustic signal generator 52 is connected to the signal inputterminal 50 through a data receiving cable 51. The acoustic signalgenerator 52 is composed of a personal computer, deck, or the like.

[0286] According to the present invention, when the portable informationterminal 1 is allowed to function as an external acoustic loudspeakerand adding a function for reproducing sounds from other sound source,the portable information terminal 1 becomes possible to respond muchmore sound data.

[0287] Furthermore, it is constituted as a first modified example in thetwentieth embodiment of the invention in such that a plurality ofacoustic sound generators 52 is connected to a portable informationterminal 1, and any of acoustic sound generators is changed over by aswitch as an input source, whereby sounds from a plurality of soundsources can be easily compared with each other, so that convenience iselevated.

[0288] Moreover, it is constituted as a second modified example in thetwentieth embodiment of the invention in such that an acousticloudspeaker serving also as speaking microphone 42, and an acousticloudspeaker serving also as receiving speaker 43 are arranged to beloudspeakers capable of functioning with no use of amplifier in case ofreproducing input signals from the outside, whereby it becomes possibleto reproduce sounds in a condition where a power supply has been shutoffin a portable information terminal 1 itself. As a result, electricityfor the portable information terminal 1 is saved to increase aserviceable time for a single charge, whereby it becomes possible toreproduce sounds of high acousticity irrespective of a remaining amountof battery.

[0289] The same effect can be attained in case of employing usualacoustic loudspeakers in place of the above-described acousticloudspeaker serving also as speaking microphone, and the acousticloudspeaker serving also as receiving speaker.

[0290] Besides, it is constituted as a third modified example in thetwentieth embodiment of the invention in such that a portableinformation terminal 1 acquires acoustic sound data from an acousticsound signal generator 52 by means of radio wave, for example, Bluetoothor the like. In this case, since no cable is used, a constitution of asystem can be simplified.

[0291]FIG. 46 is a view showing a schematic structure of a twenty firstembodiment of a sound reproducing system in a portable informationterminal according to the present invention.

[0292] As shown in the present figures, in comparison with FIG. 40, aheadphone-mounting terminal 53 is provided on a portable informationterminal 1, and a headphone 54 is connected to the headphone-mountingterminal 53 through a data receiving cable 51.

[0293] According to such arrangement as described above, it is possibleto listen stereo sounds by means of the headphone 54 in a place wheresounds should not be produced in an environment such as public places,and library.

[0294] Moreover, it is constituted as a first modified example in thetwenty first embodiment of the invention in such that reproductionsounds are reproduced from a receiving speaker in a portable informationterminal 1, and at the same time, such sounds are transmitted togetherwith telephone message to be reproduced from another receiving speakerof the communicating other party in a place such as public places wheresounds should not be listened by the third party.

[0295] As a result, no remarkable harassment arises with respect to asurrounding area, and communication accompanied with comfortable BGM canbe realized through telephone conversation.

[0296] Furthermore, when any of sounds of noise in station, hustle andbustle, pink gin in department store, lush house and the like isselected as a background effect, more pleasant communication can bepromoted.

INDUSTRIAL APPLICABILITY

[0297] As described above, according to the present invention, aportable information terminal is provided with a plurality of acousticloudspeakers, at least two of the acoustic loudspeakers aresimultaneously driven while compensating their reproduced sounds witheach other, so that comfortable and high-quality sounds can bereproduced by a single portable information terminal without using anyheadphone, earphone, external speaker system and the like, whereby aportable information terminal having high adaptability and highconvenience with respect to operating environment can be realized.

1. A reproducing system in a portable information terminal,characterized in that: the portable information terminal is providedwith at least two acoustic loudspeakers; and said at least two acousticloudspeakers are driven simultaneously to compensate their reproducedsounds with each other.
 2. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that: saidat least two acoustic loudspeakers are either disposed on said portableinformation terminal in a longitudinal direction thereof, or disposeddiagonally at the opposite ends of the portable information terminal. 3.The reproducing system in a portable information terminal as claimed inclaim 1, characterized in that: at least one member selected from saidat least two acoustic loudspeakers is located at a certain angle withrespect to a cabinet wall of said portable information terminal.
 4. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: an angle defined by at least oneacoustic loudspeaker selected from said at least two acousticloudspeakers and said cabinet wall of the portable information terminalcan be freely changed.
 5. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that: eachangle of said at least two acoustic loudspeakers may be freely changed.6. The reproducing system in a portable information terminal as claimedin claim 1, characterized in that: a cross talk barrier is placedbetween said at least two acoustic loudspeakers, and said cross talkbarrier prevents from generating cross talk from individual acousticloudspeakers.
 7. The reproducing system in a portable informationterminal as claimed in claim 6, characterized in that: said cross talkbarrier is collapsible or detachable.
 8. The reproducing system in aportable information terminal as claimed in claim 1, characterized inthat: said portable information terminal is provided with a signalprocessing circuit for eliminating cross talk; and said signalprocessing circuit for eliminating cross talk processes input signals ofsaid at least two acoustic loudspeakers to eliminate cross talk.
 9. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: at least one member selected from saidat least two acoustic loudspeakers is located at a fallen position froma position of a cabinet wall of the portable information terminal. 10.The reproducing system in a portable information terminal as claimed inclaim 9, characterized in that: either a part or the whole of said atleast one acoustic loudspeaker is covered with a perforated section of acabinet wall of said portable information terminal, or a cabinet wallcovering a vibrating surface of said loudspeaker is removed.
 11. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: at least one acoustic loudspeakerselected from said at least two acoustic loudspeakers is protruded froma side of opposite ends of said portable information terminal.
 12. Thereproducing system in a portable information terminal as claimed inclaim 11, characterized in that: said at least one acoustic loudspeakeris located at a deeper position from the front of said portableinformation terminal; and either a part of said at least one acousticloudspeaker is covered with a perforated section of a cabinet wall ofsaid portable information terminal, or a cabinet wall covering avibrating surface of said at least one acoustic loudspeaker is removed.13. The reproducing system in a portable information terminal as claimedin claim 11, characterized in that: said at least one protruded acousticloudspeaker is contained inside said portable information terminal. 14.The reproducing system in a portable information terminal as claimed inclaim 1, characterized in that: said at least two acoustic loudspeakersare arranged in a row of a speaker array in said portable informationterminal.
 15. The reproducing system in a portable information terminalas claimed in claim 1, characterized in that: said at least two acousticloudspeakers are arranged in said portable information terminal so as todirect different directions from one another.
 16. The reproducing systemin a portable information terminal as claimed in claim 15, characterizedin that: said at least two acoustic loudspeakers reproduce sounds insuch that different sounds are listened individually in differentdirections.
 17. The reproducing system in a portable informationterminal as claimed in claim 1, characterized in that: said portableinformation terminal is provided with a signal processing circuit forconverging directivity; and said signal processing circuit forconverging directivity processes input signals of said at least twoacoustic loudspeakers to converge directions of directivity.
 18. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: said portable information terminal isprovided with an omnidirectional signal processing circuit; and saidomnidirectional signal processing circuit processes input signals ofsaid at least two acoustic loudspeakers to make them omnidirectional.19. The reproducing system in a portable information terminal as claimedin claim 1, characterized in that: said portable information terminal isprovided with a signal processing circuit for converging directions ofsaid at least two acoustic loudspeakers with respect to theirdirectivities and an omnidirectional signal processing circuit formaking said at least two acoustic loudspeakers omnidirectional; and saidsignal processing circuit for converging directivity and saidomnidirectional signal processing circuit are selected alternatively.20. The reproducing system in a portable information terminal as claimedin claim 1, characterized in that: said at least two acousticloudspeakers having high efficiency are used, whereby it becomespossible to drive said at least two acoustic loudspeakers in case ofreproducing sounds without employing any amplifier.
 21. The reproducingsystem in a portable information terminal as claimed in claim 1,characterized in that: individual sounds are reproduced from said atleast two acoustic loudspeakers; and sound volumes of the individualsounds can be uniquely adjusted.
 22. The reproducing system in aportable information terminal as claimed in claim 1, characterized inthat: said at least two acoustic loudspeakers have characteristicsspecialized to middle- to high-pitched tone ranges, and that specializedto a low-pitched tone range, respectively.
 23. The reproducing system ina portable information terminal as claimed in claim 1, characterized inthat: at least one member selected from said at least two acousticloudspeakers is arranged in such that when said portable informationterminal is placed to be in contact with a plane including a desk, afloor, and a wall surface, said at least one acoustic loudspeaker canutilize reflection of sounds.
 24. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that: atleast one member selected from said at least two acoustic loudspeakerscan reproduce sounds simultaneously with a phone call by means of saidportable information terminal.
 25. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that:acoustic sound reproducing signals of said at least one acousticloudspeaker are transmitted so as to be able to listen also by the otherparty of communication.
 26. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that: atleast one member selected from said at least two acoustic loudspeakersis the one serving both as a acoustic loudspeaker and a device of saidportable information terminal including an acoustic loudspeaker servingalso as a speaking microphone, an acoustic loudspeaker serving also as areceiving speaker, an acoustic loudspeaker serving also as a ringer, anacoustic loudspeaker serving also as a vibrator, an acoustic loudspeakerserving also as a screen display monitor, and an acoustic loudspeakerserving also as a key panel.
 27. The reproducing system in a portableinformation terminal as claimed in claim 1, characterized in that: anacoustic signal generator is connected to said portable informationterminal; said acoustic signal generator stores acoustic sound data; andsaid at least two acoustic loudspeakers reproduce sounds based on saidacoustic sound data obtained from said acoustic signal generator. 28.The reproducing system in a portable information terminal as claimed inclaim 27, characterized in that: a plurality of said acoustic signalgenerators is connected to said portable information terminal; and anyof the acoustic signal generators from which data is to be acquired ischanged over by a switch.
 29. The reproducing system in a portableinformation terminal as claimed in claim 27, characterized in that: saidat least two acoustic loudspeakers are allowed to be able to reproducesounds without employing any amplifier; and they are made to be able toreproduce sounds of said acoustic sound data obtained from said acousticsignal generator in a condition where a power supply in said portableinformation terminal itself has been shut off.
 30. The reproducingsystem in a portable information terminal as claimed in claim 27,characterized in that: said portable information terminal acquires datafrom said acoustic signal generator through radio wave.
 31. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: a headphone or an earphone is connectedto said portable information terminal; and reproduced sounds arelistened by means of said headphone or earphone in place of said atleast two acoustic loudspeakers.
 32. The reproducing system in aportable information terminal as claimed in claim 31, characterized inthat: reproduced sounds from said at least two acoustic loudspeakers arelistened simultaneously with a communication message in said portableinformation terminal by means of said headphone or earphone.
 33. Thereproducing system in a portable information terminal as claimed inclaim 1, characterized in that: said portable information terminal isextensible.
 34. The reproducing system in a portable informationterminal as claimed in claim 1, characterized in that: said portableinformation terminal is collapsible.
 35. A method for reproducing soundsin a portable information terminal, characterized in that: at least twoacoustic loudspeakers disposed in the portable information terminal aredriven at the same time to compensate reproduced sounds with each other.